1. Field of the Invention
The present invention relates generally to micro-actuators, and particularly to switching of micromirrors in microelectromechanical systems (MEMS).
2. Technical Background
Micromechanical actuators are essential for microelectromechanical systems (MEMS) that require movable components. For applications such as a free-space optical fiber switch or for self-assembly of a three-dimensional MEMS structure, a compact actuator with long-range fast-speed traveling ability is often necessary. Known actuators have mechanical power transmission mechanisms based on an electrostatic driving element, such as scratch drive actuators, resonator-based vibromotors, microengines and stepper motors. Most of the devices, however, require not only large areas ( greater than 1 mm2) but also large driving voltages (10""s of volts to more than 100 volts). Moreover, either two sets of actuators or complicated phase-matching operation is required for the actuators to have a two-direction actuation capability. As multiple devices are needed on a chip, the actuators desired need to occupy a sufficiently small space and be driven using low voltages. It is further desired to be able to change the direction of the actuator by simply adjusting the applied electrical current, in order to save space and simplify the power supply design of the MEMS